<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02_JS变量与常量</title>
</head>
<body>
<script>
    //JS是一门弱类型语言
    //JS使用var 定义变量
    var a = 1;
    console.log(a);
    var b = 3.14;
    console.log(b);
    var c = "hello world";
    console.log(c);
    var d = true;
    console.log(d);
    var a = "1";
    console.log(a);

    //let
    let ab = 1;
    console.log(ab);

    //const
    const PI = 3.14;
    console.log(PI);


</script>

</body>
</html>